Project description:Fragile X-associated tremor/ataxia syndrome (FXTAS) is a severe neurodegenerative movement disorder affecting over 40% of male and 16% of female FMR1 premutation carriers over the age of 50. However, there is a lack of prognostic biomarkers to aid early diagnosis and treatment planning. Therefore, this study aimed to assess the utility of the Magnetic Resonance Parkinson Index (MRPI) as a potential MRI biomarker for FXTAS. The four measurements required for the MRPI were assessed in 45 male premutation carriers at risk of developing FXTAS (Mean age = 59.54 years), 53 male patients with FXTAS (Mean age = 66.16 years) and 61 male controls (Mean age = 60.75 years), of which 73 participants had follow-up visits on average 1.96 years later. Middle cerebellar peduncle (MCP) width as well as midbrain and pons cross-sectional area were reduced in patients with FXTAS compared to both premutation carriers without FXTAS and controls. While these measurements were not found to change over time in the three-group analysis, age was an important predictor of midbrain cross-sectional area and pons/midbrain ratio. MCP width was initially reduced in a subset of premutation carriers who developed FXTAS symptoms between their initial and follow-up visits, which also decreased between visits, compared to age-matched premutation carriers who did not show any FXTAS symptom development over time. Therefore, while the MPRI may not be a useful biomarker for FXTAS, decreased MCP width may be one of the first notable signs of FXTAS, and therefore the first biomarker with the potential to identify those most at risk for the disorder.
Project description:Charcot-Marie-Tooth disease (CMT) 2A with optic atrophy is referred to as hereditary motor and sensory neuropathy type VI (HMSN VI) and is caused by mitofusin 2 gene (MFN2) mutation. In patients with MFN2 related CMT, central nervous system is known to be also involved and cerebral white matter is mostly involved. We report a patient confirmed as HMSN VI who had isolated bilateral middle cerebellar peduncular lesions in brain MRI.
Project description:Multiple system atrophy (MSA) is a neurodegenerative disorder that presents as parkinsonism, cerebellar ataxia, and autonomic dysfunction. Magnetic resonance imaging (MRI) findings of MSA are reported to be the atrophy of the putamen/pons/cerebellum, hot cross bun sign, and bright middle cerebellar peduncle (MCP) sign. Here, we assessed the sensitivity of detecting the bright MCP sign in patients with MSA cerebellar variant (MSA-C) using a double inversion recovery (DIR) procedure, comparing it to the sensitivity of detection by T2-weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences on conventional MRI. We evaluated 6 MSA-C patients and 6 control patients (multiple sclerosis, neuromyelitis optica, and spinocerebellar atrophy). Characteristics of all the patients were collected, and MRI was analyzed. Two neurologists independently evaluated the visualization of the bright MCP sign using a 4-point visual grade from Grade 0 to Grade 3. Differences in grade between DIR and T2WI or FLAIR were statistically analyzed. Also, as a quantitative analysis, the signal intensity of the MCP lesion was compared with that of the ipsilateral thalamus, and the MCP/thalamus ratio was evaluated. As a result, DIR more sensitively showed the bright MCP signs of MSA-C patients than T2WI or FLAIR. Also, the bright MCP sign deteriorated and expanded over time in the cases we followed with MRI. We also evaluated hot cross bun sign in the pons, but the hot cross bun sign in MSA-C patients was not significantly different between the DIR and conventional MRI sequences. The DIR procedure can be a more sensitive method for detecting the involvement of MCP lesions in MSA-C.
Project description:The posterior reversible encephalopathy syndrome (PRES) is a neurological disorder of (sub)acute onset characterized by varied neurological symptoms, which may include headache, impaired visual acuity or visual field deficits, disorders of consciousness, confusion, seizures, and focal neurological deficits. In a majority of patients the clinical presentation includes elevated arterial blood pressure up to hypertensive emergencies. Neuroimaging, in particular magnetic resonance imaging, frequently shows a distinctive parieto-occipital pattern with a symmetric distribution of changes reflecting vasogenic edema. PRES frequently develops in the context of cytotoxic medication, (pre)eclampsia, sepsis, renal disease or autoimmune disorders. The treatment is symptomatic and is determined by the underlying condition. The overall prognosis is favorable, since clinical symptoms as well as imaging lesions are reversible in most patients. However, neurological sequelae including long-term epilepsy may persist in individual cases.
Project description:Patients with the ciliopathy Joubert syndrome present with physical anomalies, intellectual disability, and a hindbrain malformation described as the "molar tooth sign" due to its appearance on an MRI. This radiological abnormality results from a combination of hypoplasia of the cerebellar vermis and inappropriate targeting of the white matter tracts of the superior cerebellar peduncles. ARL13B is a cilia-enriched regulatory GTPase established to regulate cell fate, cell proliferation, and axon guidance through vertebrate Hedgehog signaling. In patients, mutations in ARL13B cause Joubert syndrome. To understand the etiology of the molar tooth sign, we used mouse models to investigate the role of ARL13B during cerebellar development. We found that ARL13B regulates superior cerebellar peduncle targeting and these fiber tracts require Hedgehog signaling for proper guidance. However, in mouse, the Joubert-causing R79Q mutation in ARL13B does not disrupt Hedgehog signaling nor does it impact tract targeting. We found a small cerebellar vermis in mice lacking ARL13B function but no cerebellar vermis hypoplasia in mice expressing the Joubert-causing R79Q mutation. In addition, mice expressing a cilia-excluded variant of ARL13B that transduces Hedgehog normally showed normal tract targeting and vermis width. Taken together, our data indicate that ARL13B is critical for the control of cerebellar vermis width as well as superior cerebellar peduncle axon guidance, likely via Hedgehog signaling. Thus, our work highlights the complexity of ARL13B in molar tooth sign etiology.
Project description:BackgroundThe standardized T1-weighted/T2-weighted (sT1w/T2w) ratio for the middle cerebellar peduncle (MCP) has been reported to be sensitive for detecting degenerative changes in the cerebellar subtype of multiple system atrophy (MSA-C), even in the early stages. We aimed to investigate the diagnostic value of the MCP sT1w/T2w ratio for differentiating between MSA-C and spinocerebellar ataxia (SCA).MethodsWe included 32 MSA-C, 8 SCA type 3 (SCA3), 16 SCA type 6 (SCA6) patients, and 17 controls, and the MCP sT1w/T2w ratio was analyzed using a region-of-interest approach. The diagnostic performance of the MCP sT1w/T2w ratio in discriminating among MSA-C, SCA3, and SCA6 was assessed and compared with diagnosis based on visual interpretation of MCP hyperintensities and the "hot cross bun" (HCB) sign.ResultsMCP sT1w/T2w ratio values were markedly lower in patients with MSA-C than in those with SCA3, those with SCA6, and controls (p < 0.001). The MCP sT1w/T2w ratio showed high diagnostic accuracy for distinguishing MSA-C from SCA3 (area under curve = 0.934), SCA6 (area under curve = 0.965), and controls (area under curve = 0.980). The diagnostic accuracy of the MCP sT1w/T2w ratio for differentiating MSA-C from SCA3 or SCA6 (90.0% for MSA-C vs. SCA3, and 91.7% for MSA-C vs. SCA6) was comparable to or superior than that of visual interpretation of MCP hyperintensities (80.0-87.5% in MSA-C vs. SCA3 and 87.6-97.9% in MSA-C vs. SCA6) or the HCB sign (72.5-80.0% in MSA-C vs. SCA3 and 77.1-93.8% in MSA-C vs. SCA6).ConclusionsThe MCP sT1w/T2w ratio might be a sensitive imaging-based marker for detecting MSA-C-related changes and differentiating MSA-C from SCA3 or SCA6.
Project description:AudienceEmergency medicine residents of all levels.IntroductionPosterior reversible encephalopathy syndrome (PRES) is a clinically significant cause of seizures, headache, neurologic deficit, and hypertensive emergency that is not uncommon in the emergency department. Posterior reversible encephalopathy syndrome was initially described as a clinical syndrome in 1996.1 It is an important cause of hypertensive emergency that is not often covered in depth in the emergency medicine curriculum since the true incidence and disease process continues to be researched.Populations who are at most risk for PRES include those with chronic hypertension, chronic renal disease, autoimmune disease, and immune suppression.2 Patients with PRES will often present with varied forms of encephalopathy and sometimes even focal neurologic symptoms that would suggest a cerebral vascular accident. These neurologic symptoms can include visual complaints and headache. Seizures are also frequently reported in association with PRES.3Early identification and appropriate management of PRES decreases morbidity and mortality without chronic neurologic sequelae. The pillars of diagnosis and management can be initiated in the emergency department. This includes a diagnosis made by a thorough history and physical exam and cerebral imaging.4 The mainstay of management is parenteral anti-hypertensives with proper blood pressure monitoring.5.Educational objectivesBy the end of the simulation, the learner will be able to: 1) manage an acute seizure 2) discuss imaging modalities to diagnose PRES 3) discuss medical management of PRES.Educational methodsThis simulation exercise is meant to be presented as a traditional medium-to-high-fidelity medical simulation case. With minor adjustments, it could be utilized as a low-fidelity case or an oral exam case.Research methodsThe educational content and general usefulness of this simulation was evaluated by open verbal (qualitative) feedback from a convenience sample of random participants following a completion of the case and debriefing by a participant group (n=30) of emergency medicine residents at a large 3-year residency training program.ResultsThe overall feedback was positive. Participants felt that it was a good opportunity to practice identifying PRES and managing it in a safe learning environment. They especially appreciated learning more about the pathophysiology of PRES, the high-risk factors for PRES, and management of the condition.DiscussionPosterior reversible encephalopathy syndrome, an uncommon condition, presents similar to many other benign and common complaints. It is crucial to be able to differentiate PRES from other causes of headache, visual disturbance, and seizures. It is important to keep PRES in mind when considering hypertensive emergencies. Many PGY-1 residents struggled to diagnose and treat PRES because it was often not on their differential, and this case helped broaden their differential. PGY-2 and PGY-3 were more frequently able to appropriately diagnose and treat PRES in this patient but found the case to be helpful in their decision-making and learning more about PRES pathophysiology. This case and associated high-yield debriefing session were effective for learners of all levels.TopicsPosterior reversible encephalopathy syndrome (PRES), altered mental status, seizure, headache, hypertensive emergency.
Project description:BackgroundThe cerebellum receives afferent signals from spinocerebellar pathways regulating lower limb movements. However, the longitudinal changes in the spinocerebellar pathway in the early stage of unilateral supratentorial stroke and their potential clinical significance have received little attention.MethodsDiffusion tensor imaging and Fugl-Meyer assessment of lower limb were performed 1, 4, and 12 weeks after onset in 33 patients with acute subcortical infarction involving the supratentorial areas, and in 33 healthy subjects. We evaluated group differences in diffusion metrics in the bilateral inferior cerebellar peduncle (ICP) and analyzed the correlation between ICP diffusion metrics and changes to the Fugl-Meyer scores of the affected lower limb within 12 weeks after stroke.ResultsSignificantly decreased fractional anisotropy and increased mean diffusivity were found in the contralesional ICP at week 12 after stroke compared to controls (all P < 0.01) and those at week 1 (all P < 0.05). There were significant fractional anisotropy decreases in the ipsilesional ICP at week 4 (P = 0.008) and week 12 (P = 0.004) compared to controls. Both fractional anisotropy (rs = 0.416, P = 0.025) and mean diffusivity (rs = -0.507, P = 0.005) changes in the contralesional ICP correlated with changes in Fugl-Meyer scores of the affected lower limb in all patients.ConclusionsBilateral ICP degeneration occurs in the early phase of supratentorial stroke, and diffusion metric values of the contralesional ICP are useful indicators of affected lower limb function after supratentorial stroke.